1. Field of the Invention
The present invention relates to apparatus for demoisturizing coal and more particularly, to an apparatus for mechanically separating water from coal fines.
2. Description of the Prior Art
The mechanical extraction of water using opposingly rotating rollers has been the subject of earlier patents. For example, U.S. Pat. No. 4,919,824, issued Apr. 24, 1990 to John L. Creps et al., discloses methods and an apparatus for deliquifying solids. The apparatus includes a vibrating inlet chute, a pair of contra-rotating rollers, and separate liquid and solid collection areas. One of the rollers may have slots along its surface, allowing water to drain to the center of the roller. In operation, this device requires a deliquified solid product to be scraped off the outlet surfaces of the rollers. This patent does not teach the use of one roller as a delivery vehicle to the compression zone, nor does it teach the use of mated compression dyes. Further, this device is not specifically adapted for water removal from coal or coal slurry. U.S. Pat. No. 958,068, issued May 7, 1910 to Alessander J. Arbuckle, discloses another apparatus for separating solid matter from liquids. This apparatus utilizes pressure generated between two contra-rotating rollers. Rather than squeezing liquid out of the solid, the rollers here deliver solids from a settling hopper.
Solids have been mechanically separated from slurries, including coal slurries, using continuous filter belt presses. Though many of these presses feature rollers to apply pressure, the main mechanism for separation is a belt having a porous structure sufficient to allow water to drain therethrough while holding solid matter. U.S. Pat. No. 3,741,388, issued Jun. 26, 1973 to Kenji Takahashi, and No. 5,236,596, issued Aug. 17, 1993 to Edward Greenwald, Sr., are examples of such devices. U.S. Pat. No. 994,495, issued Jun. 6, 1911 to John J. Berrigan, discloses a continuous belt device which features wells in the belt and protrusions on a compressive roller.
The use of wells or dies in compressive rotary members is known in the briquetting field. Though not expressly for the separation of liquids from solids, some dewatering is known to be the result of their use. The majority of these devices include removable female dies on both rollers, such as that shown in U.S. Pat. No. 2,958,902, issued Nov. 8, 1960 to Johannes B. Decker et al., and No. 3,907,485, issued Sep. 23, 1975 to Karl R. Komarek. A device for creating molded articles which includes mating male and female dies on opposing rollers is disclosed by Marshall E. Hunter et al., in U.S. Pat. No. 492,206, issued Feb. 21, 1893. Hydraulic systems used for ejecting compressed articles is disclosed by U.S. Pat. No. 57,303, issued Aug. 21, 1866 to A. H. Emery.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.